Rep. Alexandria Ocasio-Cortez (D-NY) is under fire from her Democratic colleagues in the Senate over her far-left policies and social media antics, with some calling the self-avowed Democratic-socialist “the flavor of the month” and her positions “crazy.”

Ocasio-Cortez rocketed to national prominence after shocking the political world by ousting 10-term Rep. Joe Crowley (D-NY) in New York’s 14th congressional district primary in June. The 29-year-old has quickly established a name for herself by pushing radical policies, including “Medicare for All,” the abolishment of ICE, and perhaps most notably, the “Green New Deal” — a proposed nationwide shift to non-combustible energy sources financed in (very small) part by a proposed 70% tax on top earners. However, her policy prescriptions and support of grassroots efforts to unseat incumbents within her own party have lawmakers in both chambers of Congress grumbling.

“I’m sure Ms. Cortez means well, but there’s almost an outstanding rule: Don’t attack your own people,” said Rep. Emanuel Cleaver (D-MO) told Politico. “We just don’t need sniping in our Democratic Caucus.”

“Her views don’t represent a lot of my constituents,” Sen. Jeanne Shaheen (D-NH) said of Ocasio-Cortez to The Hill. Sen. Doug Jones (D-AL) agrees with Shaheen, who told The Hill that Ocasio-Cortez becoming the face of the Democratic Party hurts its brand. “I think it skews what’s really there for the Democratic Party,” Jones, the Senate’s most vulnerable member, said. He warned that if House Democrats attempt a far-left agenda, its legislative accomplishments will be few and far between. “If the House did all the crazy things on the left that the House did on the right for the last two years, that’s not going to happen,” the Alabama Democrat said.

Sen. Jon Tester (D-MT), who won reelection narrowly, defeating Republican Matt Rosendale after a hard-fought campaign, believes Ocasio-Cortez’s celebrity will taper off.  “I hope she has a great, successful career,” said Tester. “I was here when they elected the guy [Sen. Scott Brown] from Massachusetts and he was a flavor of the month.”

“I was a flavor of the month for a while,” Tester added. “Flavors of the month come and go. She’s a flavor of the month right now. My guess is she’ll come, she’ll go. It’s the way the system works.”

The freshman congressman has also garnered criticism from former Democrat lawmakers — notably ex-Sen. Joe Liberman (I-CT) — who recently said Ocasio-Cortez’s call for a 70% marginal tax rate is proof that she does not represent the “future” of her party.”

“With all respect, I certainly hope she’s not the future and I don’t believe she is,” Lieberman, who retired in 2013 after serving nearly 25 years in the Senate, told the Fox Business Network last Thursday.

“If you look at the majority of new Democrats in the house, they tend to be, I say, center-left, if they are not left-left,” the Democrat-turned-Independent continued. “And that is because they had to be center-left to win some of those competitive swing districts that they took from Republicans. So that’s the hope.”

On the subject of Ocasio-Cortez’s proposed 70% marginal tax rate to fund her “Green New Deal,” Lieberman said a progressive tax system already exists in the U.S. “If you… accumulate income in the country the big bump is still in the middle class,” he said. “So you’ve got to be careful about raising taxes too high… a 70 percent tax on high-income people is really done for political reasons.”

Flexing her Twitter muscle — where, according to Axios, her account has become one of the platform’s most influential — Ocasio-Cortez quote-tweeted Lieberman’s remarks with: “New party, who dis?” The exchange is the latest sign of brewing tensions between the party’s progressive and establishment members.